Mixing device for gases carrying



1934- R. M. HARDGROVE 1,941,471

MIXING DEVICE FOR GASES CARRYING SOLID PARTICLES ori inal Filed July 12, 1928 2 Sheets-Sheet 1 FIG 5. FIG-4. FIG 2.

W J N/Wz/ ATTORNEY Jan. 2, 1934. R M HARDGRQVE 1,941,471

6 MIXING DEVICE FOR GASES CARRYING SOLID PARTICLES Original Filed July 12, 1928 2 Sheets-Sheet 2 ATTORNEY Patented Jan. 2, 1934 PATENT OFFICE MIXING DEVICE FOR GASES CARRYING SOLID PARTICLES Ralph M. Hardgrove,.Westfield, N. J., assignor to Fuller Lehigh Company, Fullerton, Pa., a corporation of Delaware Application July 12, 1928, Serial No. 292,148

Renewed April 8, 1933 10 Claims. (01. 302-28) 1 This invention relates to a device by means of which the particles of solid material being transferred by means of a gas stream, or the like, can be thoroughly mixed with the stream to overcome the tendency for stratification or concentration of the solid particles from taking place in portions of the stream and to make the solids become uniformly distributed in the stream. The invention will be understood from the description in connection with the accompanying drawings in which Fig. 1 is a longitudinal section through a fuel burner showing the device in place; Fig. 2 is a section along the line 22 of Fig. 1; Fig. 3 is a similar section through a modification; Fig. 4 is a section along the line 4-4 of Fig. 3; Fig. 5 is a side view partly in section showing the invention applied to the outlet of a fan; Fig. 6 is a section along the line 66 of Fig. 5; and Fig. 7 is a section along the line 7-7 of Fig. 5.

In the drawings, reference character 1 indicates a conduit leading to a fuel burner through which conduit pulverized coal, for example, may be passed by means of a stream of air passing through the conduit. The conduit is indicated as being bent at 2 just before it reaches the burner. It has been found that in such installations there is a marked tendency for the solid particles of coal being carried by the air to be flung out along the side of the longer curvature, thus causing a non-uniform distribution of the coal in the air stream when it emerges from the burner. By the present invention the distribution of the coal in the air stream is made uniform and better combustion results are obtained. The outlet of the conduit is indicated at 3 and terminates at the entrance to the furnace wall 4. The secondary air inlet 5 of a well known type, is illustrated in front of the furnace opening and an oil burner 6 extends through the primary air and coal conduit. A deflector 7, of the well known type, is placed at the outlet end of the oil burner.

For the purpose of making a uniform distribution of the coal in the air stream a plate is inserted in the conduit 1 near the end of the curve or bend 2 for the purpose of agitating and homogenizing the mixture of air and fuel particles. Thus, the plate is disposed in proximity to the bend 2 and will be seen to extend inwardly of the conduit from the side adjacent the greatest radius of the bend. In the embodiment shown in Figs. 1 and 2, the plate is shown in the form of a disc 8 that is provided with a central opening 9 of approximately the same diameter as the diameter of the conduit 1. The opening in the disc may, however, be either larger or smallerthan the diameter of the conduit. The disc 8 may be conveniently installed between flanges 10 at the ends of sections of the conduit 1. One of the flanges 10 may for convenience be provided with a circular recess of larger diameter than the diameter of the disc 8 into which recess the disc may be seated so that it can be moved transversely of the conduit 1 to vary the extent to which the metal of the disc projects into the conduit, as most clearly indicated in Fig. 2. Screws 11 may extend through or along the outside of the recess in the flange 10 in the same plane as the disc 8, so that by adjusting the screws 11, the disc 8 may be adjusted to the desired position. The plate may thus be adjusted to close the conduit in different degrees. It has been found that when the plate or portion of the disc forming the obstruction across the conduit is placed along the side where the solid particles are apt to become concentrated, the turbulence caused by the presence of the obstruction serves to make the air and solid particles become thoroughly commingled after they have passed by the obstruction.

Instead of having a disc with a hole therethrough to constitute the obstruction, the obstruction may consist of a plate of other shapes. For example, in Figs. 3 and 4, it is indicated at 15 as being a rectangular plate with the edge thereof extending a short distance into the conduit 1, the plate 15 being clamped in place between the flanges 10 and the ends of sections of the conduit.

In the illustrative embodiment shown in Figs. 5 and 6, and 7 a fan 16 is provided with an outlet 17 leading to a conduit 18. The disc 8 provided with a hole 9 is installed between the flanges 10 so that the portion of the disc 8 that extends into the conduit lies along the side where the solid particles are most apt to become concentrated in the air stream. The pipe or conduit 18 is provided with radial partitions 19 located at a distance of one or two diameters of the pipe 18 from the disc 8. The partitions 19 divide the pipe 18 into 3 equal sector shaped openings, from each of which a branch pipe 20 leads away. The turbulence caused by the obstruction projecting into 1- the conduit thoroughly mingles the air and particles of solid matter so that the mixtures passing through the several branches 20 are uniform.

I claim:

1. In a conduit having a bend therein through which finely divided material is carried by a gas, a transverse plate in proximity to the bend extending inwardly of said conduit from the side adjacent the greatest radius of the bend.

2. In a conduit through which finely divided 2 material is carried by a gas, a transverse plate extending inwardly at the side where the material is apt to become concentrated in the gas.

3. In a conduit having a bend therein through which finely divided material is carried by a gas, a transverse thin plate in proximity to the. bend extending inwardly of said conduit from the side adjacent the greatest radius of the bend partly closing the conduit.

4. In a conduit having a bend therein through which finely divided material is carried by a gas, a transverse thin plate in proximity to the bend extending inwardly of said conduit from the side adjacent the greatest radius of the bend partly closing the conduit, said plate being adjustable to close the conduit in different degrees.

5. In a conduit through which finely divided material is carried by a gas, a bend in said conduit, and a transversely extending obstruction over which the material passes in the conduit beyond the bend on the side of the long radius of the bend.

6. In a conduit through which finely divided material is carried by a gas, a stationary obstruction in said conduit extending at substantially a right angle to the length thereof to cause turbulence in the gas when it passes by said obstruction, and a plurality of branches from said conduit beyond said obstruction.

7. In a conduit through which finely divided material is carried by a gas in greater concentration at one side of the conduit than the other, a transverse plate extending inwardly of said conduit from the side of greater material concentration.

8. In a conduit through which finely divided material is carried by a gas in greater concentration at one side of the conduit than the other, an adjustable transverse plate extending inwardly of said conduit from the side of greater material concentration.

9. In a conduit of circular cross-section through which finely divided material is carried by a gas in greater concentration at one semi-circumference of the conduit than the other, a crescentshaped plate extending transversely of the axis of said conduit and positioned within the semi-circumference of greater material concentration.

10. In a conduit through which finely divided material is carried by a gas in greater concentration at one side of the conduit than the other, a flow-obstructing plate extendingv transversely of the axis and inwardly of. said conduit from the side of greater material concentration and R. M. HARDGROVE. 

